Headless compression screw driver system

ABSTRACT

A compression screw driver system including a drive member having a shaft extending from a proximal end to a distal end. A drive selection member is positioned about the shaft and is axially moveable along the shaft between an engagement position and a disengaged position. A distal portion of the drive selection member defines a first engagement structure. A compression sleeve is positioned over the distal end of the shaft. The proximal end of the compression sleeve defines a second engagement structure which complements the first engagement structure and the distal end of the compression sleeve defines a contact surface. In the engagement position the first and second engagement structures are engaged and the compression sleeve rotates with the drive member and in the disengaged position the first and second engagement structures are disengaged and the compression sleeve remains stationary while the drive member rotates.

FIELD

The present disclosure relates to headless compression screws. Moreparticularly, the disclosure relates to headless compression screwdriver systems and methods for implanting headless compression screws.

BACKGROUND

One method of reducing a fracture across two bone fragments is driving acompression screw across the fracture site. Some compression screws canhave a variable thread pitch along the length of the screw to aid incompressing the fracture while other compression screws allow the headto rotate independently from the distal threads. For fractures in areasof minimal soft tissue coverage or near articular surfaces, it can bedesirable to have a compression screw with no head, such that the screwcan be countersunk into the bone. With such screws, an insertion toolmay be used to generate compression by means of a more traditional lagtechnique.

While headless screws on the market have proven their merits clinically,the need for improvement on instrumentation, ease of use and generatedcompression has been documented in a number of papers. In more than onestudy, a loss of generated compression has been measured and documentedwith some instruments when transitioning from screwinsertion/compression to countersinking. This is likely due to the needfor the removal of the insertion handle and insertion of the cannulateddriver during a critical point in the insertion.

SUMMARY

In at least one embodiment, the present disclosure provides a drivermechanism that allows a headless compression screw to be inserted andcountersunk, without needing to change out instrumentation. The deviceshould allow improved ease-of-use for the surgeon and potentiallygreater interfragmentary compression.

In at least one embodiment, the present disclosure provides acompression screw driver system including a drive member having a shaftextending from a proximal end to a distal end with a drive tip definedon the distal end. A drive selection member is positioned about theshaft and secured thereto such that the drive selection member rotateswith the shaft and is axially moveable along the shaft between anengagement position and a disengaged position. A distal portion of thedrive selection member defines a first engagement structure. Acompression sleeve having a tubular body extending from a proximal endto a distal end with a through passage therethrough is positioned overthe distal end of the shaft with threads within the through passagethreadably engaging threads on the shaft. The proximal end of thecompression sleeve defines a second engagement structure whichcomplements the first engagement structure and the distal end of thecompression sleeve defines a contact surface. In the engagement positionthe first and second engagement structures are engaged and thecompression sleeve rotates with the drive member and in the disengagedposition the first and second engagement structures are disengaged andthe compression sleeve remains stationary while the drive memberrotates.

In at least one embodiment, the present disclosure provides a method ofimplanting a headless compression screw into a bone through a bonecontacting surface utilizing a driver system including a drive memberincluding a shaft extending from a proximal end to a distal end with adrive tip defined on the distal end; a drive selection member positionedabout the shaft and secured thereto such that the drive selection memberrotates with the shaft and is axially moveable along the shaft betweenan engagement position and a disengaged position, a distal portion ofthe drive selection member defining a first engagement structure; and acompression sleeve having a tubular body extending from a proximal endto a distal end with a through passage therethrough is positioned overthe distal end of the shaft with threads within the though passagethreadably engaging threads on the shaft, the proximal end of thecompression sleeve defines a second engagement structure whichcomplements the first engagement structure and the distal end of thecompression sleeve defines a contact surface. The method includespositioning the headless compression screw on the drive tip; rotatingthe drive member with the drive selection member in the engagementposition such that the headless compression screw is advanced into thebone and the compression sleeve is advanced until the contact surface isin contact with the bone surface; continuing to rotate the drive memberwith the drive selection member in the engagement position such that theheadless compression screw is further advanced and the compressionsleeve creates compression in the bone; moving the drive selectionmember to the disengaged position; rotating the drive member with thedrive selection member in the disengaged position such that the headlesscompression screw is further advanced into the bone and the compressionsleeve remains stationary while maintaining compression in the bone.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a bottom plan view of a headless compression screw driversystem in accordance with an embodiment of the disclosure, with thecompression sleeve disassembled from the drive member.

FIGS. 2, 3 and 4 are bottom, side and top views, respectively, of theheadless compression screw driver system of FIG. 1 with the compressionsleeve assembled on the drive member and in an engaged position.

FIGS. 5, 6 and 7 are bottom, side and top views, respectively, of theheadless compression screw driver system of FIG. 1 with the compressionsleeve assembled on the drive member and in a disengaged position.

FIG. 8 is an exploded perspective view of the drive member of FIG. 1.

FIG. 9 is a cross-sectional view of the headless compression screwdriver system.

FIG. 10 is a cross-sectional view of the headless compression screwdriver system.

FIG. 11 is an expanded perspective view of a portion of the headlesscompression screw driver system with the compression sleeve in adisengaged position.

FIGS. 12-18 are cross-sectional views showing sequential implantation ofa headless compression screw utilizing a headless compression screwdriver system in accordance with an embodiment of the invention.

DETAILED DESCRIPTION

It is to be understood that the present disclosure is not limited in itsapplication to the details of construction and the arrangement ofcomponents set forth in the description herein or illustrated in thedrawings. The teachings of the present disclosure may be used andpracticed in other embodiments and practiced or carried out in variousways. Also, it is to be understood that the phraseology and terminologyused herein is for the purpose of description and should not be regardedas limiting. The use of “including,” “comprising,” or “having” andvariations thereof herein is meant to encompass the items listedthereafter and equivalents thereof as well as additional items. Unlessspecified or limited otherwise, the terms “mounted,” “connected,”“supported,” and “coupled” and variations thereof are used broadly andencompass both direct and indirect mountings, connections, supports, andcouplings. Further, “connected” and “coupled” are not restricted tophysical or mechanical connections or couplings.

The following discussion is presented to enable a person skilled in theart to make and use embodiments of the present disclosure. Variousmodifications to the illustrated embodiments will be readily apparent tothose skilled in the art, and the principles herein can be applied toother embodiments and applications without departing from embodiments ofthe present disclosure. Thus, the embodiments are not intended to belimited to embodiments shown, but are to be accorded the widest scopeconsistent with the principles and features disclosed herein. Thefollowing detailed description is to be read with reference to thefigures, in which like elements in different figures have like referencenumerals. The figures, which are not necessarily to scale, depictselected embodiments and are not intended to limit the scope of theembodiments. Skilled artisans will recognize the examples providedherein have many useful alternatives and fall within the scope of theembodiments.

With reference to FIGS. 1-11, a headless compression screw driver system10 in accordance with an embodiment of the disclosure will be described.The headless compression screw driver system 10 generally comprises adrive member 20 and a compression sleeve 70. As will be described inmore detail hereinafter, the drive member 20 and the compression sleeve70 are configured such that the may be rotated together or the drivemember 20 may be rotated independently of the compression sleeve 70.More specifically, when a drive selection member 40 is engaged with thecompression sleeve 70, as illustrated in FIGS. 2-4, the compressionsleeve 70 rotates together with the drive member 20. This would be theposition in which the surgeon would insert the headless screw and gaininterfragmentary compression. When the drive selection member 40 isdisengaged from the compression sleeve 70, as illustrated in FIGS. 5-7,the drive member 20 rotates independently from the compression sleeve70. This would be the position where the surgeon could drive the screwout of the compression sleeve 70 and into the near-cortex tocountersink. Headless compression screw driver 10 may also have acannulated configuration such that driver 10 is configured to bedisposed over a K-wire.

Referring to FIGS. 1 and 8-11, the drive member 20 includes a shaft 22extending from a proximal end 21 to a distal end 23. The proximal end 21is configured to engage a handle or the like (not shown). For example,the illustrated embodiment includes a flat area 24 and a groove 25. Thedistal end 23 of the shaft 22 includes a screw engaging tip 26, forexample, a hexalobular drive tip, however, other configurations may beutilized. Since the shaft 22 is continuous, application of a rotationforce to the proximal end 21, via a handle or the like, causes directrotation of the screw engaging tip 26 and thereby a screw 100 positionedthereon (see FIG. 12).

A radial flange 28 extends from an intermediate portion of the shaft 22.In the illustrated embodiment, the flange 28 is formed integral with theshaft 22, but may alternatively be formed separately and attachedthereto. A transverse bore 29 extends through the flange 28 and shaft 22and is configured to receive a connecting pin 30. As described in moredetail below, the connecting pin 30 extends through slots 46 in thedrive selection member 40 and through the bore 29 to fix the driveselection member 40 on the shaft 22, with the drive selection member 40axially moveable relative to the shaft 22. The distal surface 31 of theflange 28 defines a spring stop surface.

A guide portion 32 is defined along the shaft distally of the flange 28.The guide portion 32 has a configuration which complements a distalportion 57 of the passage 45 extending through the drive selectionmember 40, as shown in FIG. 11. With such a matching configuration, thedrive selection member 40 rotates in conjunction with rotation of theshaft 22. In the illustrated embodiment, the guide portion 32 has asquared cylindrical configuration, however, other configurations may beutilized. A notch 34 is defined in the guide portion 32 and isconfigured to receive a portion 54 of a lock button 50, as will bedescribed hereinafter, to lock the drive selection member 40 in thedisengaged position, as illustrated in FIG. 10. Distally of the guideportion 32, the shaft 22 defines a plurality of threads 36 configured toengage internal threads 76 of the compression sleeve 70 such that thecompression sleeve 70 is threadably supported relative to the shaft 22.Additionally, the shaft 22 may include a groove 38, markings or the likewhich may be utilized to indicate position or depth of the drive member20 relative to the compression sleeve 70, as will be described in moredetail hereinafter.

The drive selection member 40 includes a tubular body 42 extendingbetween a proximal end 41 and a distal end 43. A through passage 45 runsthrough the tubular body 42 from the proximal end 41 to the distal end43. Finger pads 44 and/or grooves 47 may be provided along the tubularbody 42 to facilitate gripping of the drive selection member 40 andmoving it proximally to selectively disengage the drive selection member40 from the compression sleeve 70. The slots 46 extend through thetubular body 42 in an axial direction. As previously discussed, theconnection pin 30 extends into the slots 46 to lock the drive selectionmember 40 onto the shaft 22, with the slots 46 defining an axial rangeof motion of the drive selection member 40 relative to the shaft 22. Itshould also be noted that more than one pair of slots 46 may be disposedin drive selection member 40. For example, more than one pair of slots46 may be used when headless compression screw driver is configured tobe cannulated.

An engagement spring 51 is positioned within the passage 45 and extendsbetween the flange distal surface 31 and an internal shoulder 49 withinthe passage 45 (see FIG. 9). The engagement spring 51 is configured tobias the drive selection member 40 away from the flange 28, i.e.distally toward the engagement position as shown in FIG. 9. As seen inFIG. 11, the distal end of the tubular body 42 defines a plurality ofradial teeth 59 which are configured to engage radial teeth 79 on theproximal end of the compression sleeve 70 when the drive selectionmember 40 is in the engagement position. With the teeth 59, 79 engaged,the compression sleeve 70 is caused to rotate in conjunction withrotation of the shaft 22. Exemplary teeth 59, 79 may be 0.5 mm, 30degree teeth. While radial teeth are the illustrated engagementstructures, other engagement structures may be utilized,

The tubular body 42 also defines a transverse bore 48 configured toreceive the lock button 50. The lock button 50 has a body 52 whichdefines a through passage 53 which is sized and configured such that theguide portion 32 of the shaft 22 passes therethrough. A locking portion54 of the lock button body 52 extends below the through passage 53 andis configured to engage within the notch 34 defined by the guide portion32 when the drive selection member 40 is moved to the disengagedposition, as shown in FIG. 10. A lock spring 56 is supported within aguide hole 58 within the tubular body 42. The lock spring 56 isconfigured to bias the lock button 50 toward the position wherein thelocking portion 54 sits in the notch 34. As such, when a user pulls thedrive selection member 40 proximally, against the force of theengagement spring 51, the locking portion 54 of the lock button 50 willautomatically engage in the notch 34 once the drive selection member 40is in the disengaged position. The lock button 50 will maintain thedrive selection member 40 in the disengaged position until the lockbutton 50 is depressed, against the force of the lock spring 56, and thelocking portion 54 disengages with the notch 34. Upon disengagement, theguide portion 32 of the shaft 22 is free to automatically travel underthe force of the engagement spring 51 through the through passage 53 ofthe lock button 50 to the engagement position.

An exemplary compression sleeve 70 will be described with reference toFIGS. 1 and 9-11. The compression sleeve 70 has a tubular body 72extending from a proximal end 71 to a distal end 73. The proximalportion 74 of the tubular body 72 has a larger diameter compared to thedistal portion 80 of the tubular body 72. The larger diameter of theproximal portion 74 complements the diameter of the drive selectionmember 40. With such a configuration, engagement of drive selectionmember teeth 59 and compression sleeve teeth 79 provides a strongtranslation of the rotation force from the drive selection member 40 tothe compression sleeve 70.

A through passage 75 extends through the tubular body 72 from theproximal end 71 to the distal end 73. The through passage 75 is sizedsuch that the drive member shaft 22 passes therethrough. A plurality ofinternal threads 76 are defined along the through passage 75. In theillustrated embodiment, the threads 76 are at the proximal end of thethrough passage 75, however, the threads 76 may be otherwise positioned.The threads 76 are configured to threadably engage the threads 36 alongthe shaft 22. The threads 36, 76 are preferably the same pitch as thethreads 102 of the compression screw 100. With such a configuration, thethreads 36, 76 allow the screw 100 to be advanced and countersunk at thesame rate that the drive member 20 moves relative to compression sleeve70 when the drive selection member 40 is disengaged. As such, movementof the groove 38 on the shaft 22 within the window 82 defined in thedistal portion of the tubular body 72 indicates the depth that theheadless screw 100 has been advanced below the bone surface 111.

The distal end 73 of the tubular body 72 defines a contact surface 81which is configured to contact the bone surface 111 (See FIG. 14) whenthe compression sleeve 70 is advanced with the drive member 20.Continued rotation of the drive member 20, with the drive selectionmember 40 in the engaged position, will cause the contact surface 81 tofurther press against the bone surface 111 which creates a desiredcompression. Once a desired compression is achieved, the drive selectionmember 40 is moved proximally to the disengaged position. Thereafter,the drive member 20 may be further rotated to countersink the headlessscrew 100.

Having generally described the components of an exemplary headlesscompression screw driver system 10, implantation of a headless screw 100utilizing such a system will be described with reference to FIGS. 12-18.The headless screw 100 includes distal threads 102 and proximalcountersink threads 104. The headless screw 100 includes a drive recess106 which complements the drive member drive tip 26. The screw 100 isimplanted into bone portions 110, 112 with a fracture 114 therein. Thescrew 100 enters the bone portion 110 at a bone surface 111.

Referring to FIG. 12, the screw 100 is positioned on the screw tip 26with the drive selection member 40 in the engaged position. Moving toFIG. 13, the drive member 20 is rotated such that the screw threads 102are threaded through the bone surface 111 of the bone portion 110. Withthe drive selection member 40 engaged with the compression sleeve 70,the compression sleeve 70 rotates in conjunction with the drive member20, maintaining the relative position of the components. Rotation of thedrive member 20 continues with the screw 100 spanning the fracture 114and entering the bone 112. Since the compression sleeve 70 advances withthe drive member 20, the contact surface 81 eventually contacts the bonesurface 111 as illustrated in FIG. 14. As the drive member 20 continuesto be rotated, the compression sleeve 70 advances against the bonesurface 111 and causes compression of the fracture 114 as shown in FIG.15.

Turning to FIG. 16, once a desired compression is achieved, the driveselection member 40 is moved proximally to the disengaged position withthe locking portion 54 of the lock button 50 automatically moving intothe notch 34 under the force of spring 56. The lock button 50 maintainsthe drive selection member 40 in the disengaged position for theremainder of the procedure. As shown in FIG. 17, the drive member 20 isagain rotated to further advance the screw 100, with the countersinkthreads 104 entering the bone portion 110. Since the compression sleeve70 is rotationally disengaged, it does not rotate and the drive member20 and screw 100 advance relative to the compression sleeve 70. Thecompression force is maintained through engagement of the threads 76with the threads 36. The position of the groove 38 in relation to thewindow 82 of the compression sleeve 70 indicates to the surgeon thefurther depth the screw 100 has traveled. Once a desired depth has beenreached, the drive tip 26 is disengaged from the screw 100 and theprocedure is complete.

Although several embodiments of the disclosure have been disclosed inthe foregoing specification, it is understood that many modificationsand other embodiments of the disclosure will come to mind to which theinvention pertains, having the benefit of the teaching presented in theforegoing description and associated drawings. It is thus understoodthat the systems of the disclosure are not limited to the specificembodiments disclosed hereinabove, and that many modifications and otherembodiments are intended to be included within the scope of the appendedclaims. It is further envisioned that features from one embodiment maybe combined or used with the features from a different embodimentdescribed herein. Moreover, although specific terms are employed herein,as well as in the claims which follow, they are used only in a genericand descriptive sense, and not for the purposes of limiting thedescribed invention, nor the claims which follow. The entire disclosureof each patent and publication cited herein is incorporated byreference, as if each such patent or publication were individuallyincorporated by reference herein. Various features and advantages of theinvention are set forth in the following claims.

What is claimed is:
 1. A compression screw driver system comprising: a drive member including a shaft extending from a proximal end to a distal end with a drive tip defined on the distal end; a drive selection member positioned about the shaft and secured thereto such that the drive selection member rotates with the shaft and is axially moveable along the shaft between an engagement position and a disengaged position, a distal portion of the drive selection member defining a first engagement structure; and a compression sleeve having a tubular body extending from a proximal end to a distal end with a through passage therethrough is positioned over the distal end of the shaft with threads within the though passage threadably engaging threads on the shaft, the proximal end of the compression sleeve defines a second engagement structure which complements the first engagement structure and the distal end of the compression sleeve defines a contact surface, wherein in the engagement position the first and second engagement structures are engaged and the compression sleeve rotates with the drive member and in the disengaged position the first and second engagement structures are disengaged and the compression sleeve remains stationary while the drive member rotates, and wherein the proximal end of the shaft is configured for engagement with at least one of a handle and a driving tool.
 2. The system of claim 1, wherein the drive selection member includes one or more pairs of axial slots and a connection pin extends through the shaft and into the axial slots to define the axial range of motion of the drive selection member.
 3. The system of claim 1, wherein a spring within the drive selection member biases the drive selection member toward the engagement position.
 4. The system of claim 1, wherein a lock button extends into the drive selection member and is configured to engage a notch in the shaft when the drive selection member is in the disengaged position such that the lock button maintains the drive selection member in the disengaged position.
 5. The system of claim 4, wherein the lock button is biased toward engagement with the notch.
 6. The system of claim 1, wherein the first and second engagement structures are in the form of radial teeth.
 7. The system of claim 1, wherein the through passage threads and the shaft threads have a pitch equal to a pitch of threads on a screw with which the system is utilized.
 8. The system of claim 1, wherein the shaft has a marking thereon which aligns with a window of the compression sleeve and indicates relative movement of the drive member relative to the compression sleeve when rotated with the drive selection member in the disengaged position.
 9. The system of claim 8, wherein the marking is a circumferential groove.
 10. The system of claim 1, wherein the shaft includes a guide portion with a non-circular configuration which complements a non-circular portion of a through passage of the drive selection member.
 11. The system of claim 1, wherein the drive selection member includes a pair of axial slots and a connection pin extends through the shaft and into the axial slots to define the axial range of motion of the drive selection member.
 12. The system of claim 1, wherein a lock button extends into the drive selection member and is configured to engage a notch in the shaft when the drive selection member is in the disengaged position such that the lock button maintains the drive selection member in the disengaged position.
 13. The system of claim 12, wherein the lock button is biased toward engagement with the notch.
 14. The system of claim 1, wherein the shaft has a marking thereon which aligns with a window of the compression sleeve and indicates relative movement of the drive member relative to the compression sleeve when rotated with the drive selection member in the disengaged position.
 15. The system of claim 14, wherein the marking is a circumferential groove.
 16. The system of claim 1, wherein the shaft includes a guide portion with a non-circular configuration which complements a non-circular portion of a through passage of the drive selection member.
 17. A compression screw driver system comprising: a drive member including a shaft extending from a proximal end to a distal end with a drive tip defined on the distal end; a drive selection member positioned about the shaft and secured thereto such that the drive selection member rotates with the shaft and is axially moveable along the shaft between an engagement position and a disengaged position, a distal portion of the drive selection member having a first set of radial teeth; and a compression sleeve having a tubular body extending from a proximal end to a distal end with a through passage therethrough is positioned over the distal end of the shaft with threads within the though passage threadably engaging threads on the shaft, the proximal end of the compression sleeve defines a second set of radial teeth which complements the first set of radial teeth and the distal end of the compression sleeve defines a contact surface, wherein in the engagement position the first and second sets of radial teeth are engaged and the compression sleeve rotates with the drive member and in the disengaged position the first and second sets of radial teeth are disengaged and the compression sleeve remains stationary while the drive member rotates, and wherein a spring within the drive selection member biases the drive selection member toward the engagement position. 